title: Differential miRNA expression in omental adipose tissue and in the circulation of obese patients identifies novel metabolic biomarkers.
abstract: BACKGROUND
  Omental fat accumulation is associated with development of the metabolic syndrome, although its molecular characteristics are poorly understood. Mi(cro)RNAs (miRNAs), a class of small noncoding RNAs, are known to regulate various metabolic processes, although their role in obesity and the metabolic syndrome is not clearly defined. This study sought to characterize the miRNA expression in omentum, sc fat and in the circulation of obese and nonobese individuals. Their potential as noninvasive metabolic biomarkers was also explored.
  
  
  METHODS
  miRNA was extracted from paired omentum and sc fat tissues, and blood samples, from a total of 50 obese and nonobese patients. A miRNA microarray was performed and a panel of differentially expressed miRNAs validated using RQ-PCR.
  
  
  RESULTS
  The miRNA expression profiles were unique for omentum and paired sc fat; no correlation in miRNA expression was observed between these two fat depots. Expression of two miRNAs (miR-17-5p and miR-132) differed significantly between obese and nonobese omental fat (P = 0.048 and P = 0.016). This expression pattern was reflected in the circulation in which these same two miRNAs were also significantly dysregulated in blood from obese subjects. The miRNA expression in omental fat and blood from obese patients correlated significantly with body mass index, fasting blood glucose, and glycosylated hemoglobin.
  
  
  CONCLUSIONS
  This study demonstrates that candidate metabolic miRNAs are altered in adipose tissue and circulation of the obese. Omental fat tissue and systemic miRNA levels reflect components of the metabolic syndrome, highlighting their potential as novel biomarkers for this complex syndrome.
authors.affiliation: Department of Surgery, National University of Ireland, Galway, Galway, Ireland.
authors.forename: H M
authors.initials: HM
authors.lastname: Heneghan
authors.forename: N
authors.initials: N
authors.lastname: Miller
authors.forename: O J
authors.initials: OJ
authors.lastname: McAnena
authors.forename: T
authors.initials: T
authors.lastname: O'Brien
authors.forename: M J
authors.initials: MJ
authors.lastname: Kerin
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D015992:Body Mass Index; D015390:Gastric Bypass; D006146:Guanidines; D006801:Humans; D035683:MicroRNAs / Q000096:biosynthesis*; D046228:Microarray Analysis; D009765:Obesity / Q000097:blood / Q000378:metabolism* / Q000601:surgery; D009767:Obesity, Morbid / Q000097:blood / Q000378:metabolism / Q000601:surgery; D009852:Omentum / Q000378:metabolism*; D010636:Phenols; D010865:Pilot Projects; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050507:Subcutaneous Fat, Abdominal / Q000378:metabolism
chemical_list: D015415:Biomarkers; D006146:Guanidines; D035683:MicroRNAs; D010636:Phenols; C411644:trizol